linux-cve-announce - CVE-2023-54194: exfat: use kvmalloc_array/kvfree instead of kmalloc

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Message-ID: <2025123028-CVE-2023-54194-a396@gregkh>
Date: Tue, 30 Dec 2025 13:10:02 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-54194: exfat: use kvmalloc_array/kvfree instead of kmalloc_array/kfree

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

exfat: use kvmalloc_array/kvfree instead of kmalloc_array/kfree

The call stack shown below is a scenario in the Linux 4.19 kernel.
Allocating memory failed where exfat fs use kmalloc_array due to
system memory fragmentation, while the u-disk was inserted without
recognition.
Devices such as u-disk using the exfat file system are pluggable and
may be insert into the system at any time.
However, long-term running systems cannot guarantee the continuity of
physical memory. Therefore, it's necessary to address this issue.

Binder:2632_6: page allocation failure: order:4,
 mode:0x6040c0(GFP_KERNEL|__GFP_COMP), nodemask=(null)
Call trace:
[242178.097582]  dump_backtrace+0x0/0x4
[242178.097589]  dump_stack+0xf4/0x134
[242178.097598]  warn_alloc+0xd8/0x144
[242178.097603]  __alloc_pages_nodemask+0x1364/0x1384
[242178.097608]  kmalloc_order+0x2c/0x510
[242178.097612]  kmalloc_order_trace+0x40/0x16c
[242178.097618]  __kmalloc+0x360/0x408
[242178.097624]  load_alloc_bitmap+0x160/0x284
[242178.097628]  exfat_fill_super+0xa3c/0xe7c
[242178.097635]  mount_bdev+0x2e8/0x3a0
[242178.097638]  exfat_fs_mount+0x40/0x50
[242178.097643]  mount_fs+0x138/0x2e8
[242178.097649]  vfs_kern_mount+0x90/0x270
[242178.097655]  do_mount+0x798/0x173c
[242178.097659]  ksys_mount+0x114/0x1ac
[242178.097665]  __arm64_sys_mount+0x24/0x34
[242178.097671]  el0_svc_common+0xb8/0x1b8
[242178.097676]  el0_svc_handler+0x74/0x90
[242178.097681]  el0_svc+0x8/0x340

By analyzing the exfat code,we found that continuous physical memory
is not required here,so kvmalloc_array is used can solve this problem.

The Linux kernel CVE team has assigned CVE-2023-54194 to this issue.


Affected and fixed versions
===========================

	Fixed in 5.10.190 with commit 79d16a84ea41272dfcb0c00f9798ddd0edd8098d
	Fixed in 5.15.126 with commit 8a34a242cf03211cc89f68308d149b793f63c479
	Fixed in 6.1.45 with commit 1427a7e96fb90d0896f74f5bcd21feb03cc7c3d0
	Fixed in 6.4.10 with commit 0c5c3e8a2550b6b2a304b45f260296db9c09df96
	Fixed in 6.5 with commit daf60d6cca26e50d65dac374db92e58de745ad26

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2023-54194
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	fs/exfat/balloc.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/79d16a84ea41272dfcb0c00f9798ddd0edd8098d
	https://git.kernel.org/stable/c/8a34a242cf03211cc89f68308d149b793f63c479
	https://git.kernel.org/stable/c/1427a7e96fb90d0896f74f5bcd21feb03cc7c3d0
	https://git.kernel.org/stable/c/0c5c3e8a2550b6b2a304b45f260296db9c09df96
	https://git.kernel.org/stable/c/daf60d6cca26e50d65dac374db92e58de745ad26